RBL checks and Spamcop

[Paul Welsh]

Here's something I've noticed already.  The rcvd_in_osirusoft_com tag works
with similar success levels to the rcvd_in_bl_spamcop_net tag.  However,
because SpamAssassin checks all the mail headers, some false alarms from
Osirusoft are occurring.  For example, an innocent message sent from a
dialup account to a reputable ISP's mail server and from there to ours got
tagged because the dialup IP was listed by relays.osirusoft.com.  Naturally,
if I dial an ISP and they allocate me an IP address from their pool, there's
no way of me knowing whether the previous user to be assigned that IP
address was a spammer.

The way round this is to assign a negative score to the  X_OSIRU_DUL_FH tag.
This specifically checks the First Hop.

Sorry if this is a bit off-topic.